mm/vma: convert __mmap_region() to use vma_flags_t

Update the mmap() implementation logic implemented in __mmap_region() and
functions invoked by it.  The mmap_region() function converts its input
vm_flags_t parameter to a vma_flags_t value which it then passes to
__mmap_region() which uses the vma_flags_t value consistently from then
on.

As part of the change, we convert map_deny_write_exec() to using
vma_flags_t (it was incorrectly using unsigned long before), and place it
in vma.h, as it is only used internal to mm.

With this change, we eliminate the legacy is_shared_maywrite_vm_flags()
helper function which is now no longer required.

We are also able to update the MMAP_STATE() and VMG_MMAP_STATE() macros to
use the vma_flags_t value.

Finally, we update the VMA tests to reflect the change.

Link: https://lkml.kernel.org/r/1fc33a404c962f02da778da100387cc19bd62153.1774034900.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 12 insertions, 55 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 72bc5016094b..9472b3c9a22b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1522,12 +1522,6 @@ static inline bool vma_is_accessible(const struct vm_area_struct *vma)
 	return vma->vm_flags & VM_ACCESS_FLAGS;
 }
 
-static inline bool is_shared_maywrite_vm_flags(vm_flags_t vm_flags)
-{
-	return (vm_flags & (VM_SHARED | VM_MAYWRITE)) ==
-		(VM_SHARED | VM_MAYWRITE);
-}
-
 static inline bool is_shared_maywrite(const vma_flags_t *flags)
 {
 	return vma_flags_test_all(flags, VMA_SHARED_BIT, VMA_MAYWRITE_BIT);
@@ -4335,12 +4329,24 @@ static inline bool range_in_vma(const struct vm_area_struct *vma,
 
 #ifdef CONFIG_MMU
 pgprot_t vm_get_page_prot(vm_flags_t vm_flags);
+
+static inline pgprot_t vma_get_page_prot(vma_flags_t vma_flags)
+{
+	const vm_flags_t vm_flags = vma_flags_to_legacy(vma_flags);
+
+	return vm_get_page_prot(vm_flags);
+}
+
 void vma_set_page_prot(struct vm_area_struct *vma);
 #else
 static inline pgprot_t vm_get_page_prot(vm_flags_t vm_flags)
 {
 	return __pgprot(0);
 }
+static inline pgprot_t vma_get_page_prot(vma_flags_t vma_flags)
+{
+	return __pgprot(0);
+}
 static inline void vma_set_page_prot(struct vm_area_struct *vma)
 {
 	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
diff --git a/include/linux/mman.h b/include/linux/mman.h
index 0ba8a7e8b90a..389521594c69 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -170,53 +170,4 @@ static inline bool arch_memory_deny_write_exec_supported(void)
 }
 #define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_supported
 #endif
-
-/*
- * Denies creating a writable executable mapping or gaining executable permissions.
- *
- * This denies the following:
- *
- * 	a)	mmap(PROT_WRITE | PROT_EXEC)
- *
- *	b)	mmap(PROT_WRITE)
- *		mprotect(PROT_EXEC)
- *
- *	c)	mmap(PROT_WRITE)
- *		mprotect(PROT_READ)
- *		mprotect(PROT_EXEC)
- *
- * But allows the following:
- *
- *	d)	mmap(PROT_READ | PROT_EXEC)
- *		mmap(PROT_READ | PROT_EXEC | PROT_BTI)
- *
- * This is only applicable if the user has set the Memory-Deny-Write-Execute
- * (MDWE) protection mask for the current process.
- *
- * @old specifies the VMA flags the VMA originally possessed, and @new the ones
- * we propose to set.
- *
- * Return: false if proposed change is OK, true if not ok and should be denied.
- */
-static inline bool map_deny_write_exec(unsigned long old, unsigned long new)
-{
-	/* If MDWE is disabled, we have nothing to deny. */
-	if (!mm_flags_test(MMF_HAS_MDWE, current->mm))
-		return false;
-
-	/* If the new VMA is not executable, we have nothing to deny. */
-	if (!(new & VM_EXEC))
-		return false;
-
-	/* Under MDWE we do not accept newly writably executable VMAs... */
-	if (new & VM_WRITE)
-		return true;
-
-	/* ...nor previously non-executable VMAs becoming executable. */
-	if (!(old & VM_EXEC))
-		return true;
-
-	return false;
-}
-
 #endif /* _LINUX_MMAN_H */